package com.wugh.fast.kernel.core.util;

import org.springframework.aop.framework.AdvisedSupport;
import org.springframework.aop.framework.AopProxy;
import org.springframework.aop.support.AopUtils;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;

/**
 * @author 吴冠辉
 * @date 2018/1/30
 */
public class AopTargetUtils {

    /**
     * 获取 目标对象
     *
     * @param proxy 代理对象
     * @return
     * @throws Exception
     */
    public static Object getTarget(Object proxy) throws Exception {

        if (!AopUtils.isAopProxy(proxy) && !isMapperProxy(proxy)) {
            return proxy;//不是代理对象
        }
        if (AopUtils.isJdkDynamicProxy(proxy)) {
            return getJdkDynamicProxyTargetObject(proxy);
        } else if (isMapperProxy(proxy)) {
            return getMapperProxyTargetObject(proxy);
        } else { //cglib
            return getCglibProxyTargetObject(proxy);
        }
    }

    private static Object getMapperProxyTargetObject(Object proxy) {
        try {
            Field h;
            try {
                h = proxy.getClass().getDeclaredField("h");
            } catch (NoSuchFieldException e) {
                h = proxy.getClass().getSuperclass().getDeclaredField("h");
            }
            h.setAccessible(true);
            InvocationHandler invocationHandler = (InvocationHandler) h.get(proxy);
            return invocationHandler;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private static boolean isMapperProxy(Object proxy) {
        return proxy instanceof Proxy;
    }


    private static Object getCglibProxyTargetObject(Object proxy) throws Exception {
        Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0");
        h.setAccessible(true);
        Object dynamicAdvisedInterceptor = h.get(proxy);

        Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");
        advised.setAccessible(true);

        Object target = ((AdvisedSupport) advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();

        return target;
    }

    private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception {
        Field h = proxy.getClass().getSuperclass().getDeclaredField("h");
        h.setAccessible(true);
        AopProxy aopProxy = (AopProxy) h.get(proxy);

        Field advised = aopProxy.getClass().getDeclaredField("advised");
        advised.setAccessible(true);

        Object target = ((AdvisedSupport) advised.get(aopProxy)).getTargetSource().getTarget();

        return target;
    }

}
